First on the list is in fact, go to Banff. Because lets be honest here, the best thing about Calgary is its a hours drive to the Rockies.

You could walk by the river front near downtown, or go to Princess Island Park. But you'll probably find portions of it still closed from the flood. And any Calgarian you'll meet there will bore you to death complaining how their property values have fallen thanks to it.

The Calgary Tower would be a good choice.....10-15 years ago when skyscapers belonging to oil companies weren't blocking half its view.

There's Chinatown, I don't go there much myself. The fact that the Chinese Consulate is lined with barbed razor wire makes me distrust uncertain of the whole area.